How to Setup Charles Proxy for Mobile App Testing

Charles Proxy is an essential tool for mobile app testing, allowing you to intercept, inspect, and modify HTTP/HTTPS traffic between your mobile device and the internet. This guide walks you through setting up Charles Proxy for both iOS and Android devices.

✅ Prerequisites

Before you begin, make sure you have:

💻 Charles Proxy installed on your computer (Download here)
📱 A mobile device (iOS or Android)
📡 Both devices connected to the same WiFi network
🔑 Charles Proxy license (optional, but recommended for production use)

📥 Step 1: Install and Configure Charles Proxy

1.1 Download and Install

Download Charles Proxy from charlesproxy.com
Install the application on your computer
Launch Charles Proxy

1.2 Enable SSL Proxying

Charles Proxy needs to be configured to decrypt HTTPS traffic:

Go to Proxy → SSL Proxying Settings
Check Enable SSL Proxying
Click Add under SSL Proxying
Add location:
- Host: * (wildcard for all hosts)
- Port: 443
Click OK

🖥️ Step 2: Configure Your Computer

Find Your Computer's IP Address

On Mac:

ifconfig | grep "inet " | grep -v 127.0.0.1

On Windows:

ipconfig

💡 Note: Your local IP address usually starts with 192.168.x.x or 10.0.x.x

Configure Charles Proxy Port

Go to Proxy → Proxy Settings
Note the port number (default is 8888)
Keep this window open for reference

📱 Step 3: Configure Your Mobile Device

🍎 For iOS (iPhone/iPad):

Open Settings on your device
Tap Wi-Fi
Tap the (i) icon next to your connected network
Scroll down to HTTP Proxy
Select Manual
Enter:
- Server: Your computer's IP address (from Step 2)
- Port: 8888 (or your Charles port)
Tap Save

🤖 For Android:

Open Settings
Go to Network & Internet → Wi-Fi
Long-press on your connected network
Select Modify network
Tap Advanced options
Set Proxy to Manual
Enter:
- Proxy hostname: Your computer's IP address
- Proxy port: 8888
Tap Save

🔐 Step 4: Install SSL Certificate

To decrypt HTTPS traffic, your mobile device needs to trust Charles' SSL certificate.

🍎 For iOS:

On your mobile device, open Safari
Go to chls.pro/ssl (Charles SSL certificate download)
Tap Allow when prompted to download the profile
Go to Settings → Profile Downloaded
Tap Install (enter passcode if prompted)
Tap Install again to confirm
Go to Settings → General → About → Certificate Trust Settings
Enable full trust for the Charles Proxy certificate
Tap Continue to confirm

🤖 For Android:

On your mobile device, open Chrome
Go to chls.pro/ssl
Download the certificate
Go to Settings → Security → Install from storage
Select the downloaded certificate
Name it "Charles Proxy" and tap OK

✔️ Step 5: Verify the Setup

Open Charles Proxy on your computer
You should see a popup asking to allow connection from your device
Click Allow
Open any app or browser on your mobile device
You should see traffic appearing in Charles Proxy

🎉 Success! If you see traffic, you're all set up!

⚠️ Common Troubleshooting

❌ Issue: No Traffic Appearing

Solutions:

Verify both devices are on the same WiFi network
Double-check the IP address and port configuration
Restart Charles Proxy
Restart your mobile device's WiFi connection

🍎 iOS: Certificate Not Trusted

Solution:

Go to Settings → General → About → Certificate Trust Settings
Make sure Charles certificate is enabled

❌ Issue: "SSL Handshake Failed" Errors

Solutions:

Ensure SSL Proxying is enabled in Charles
Verify the certificate is properly installed on the device
Add *:443 to SSL Proxying locations

🔒 Issue: Some Apps Don't Show Traffic

Explanation: Some apps use certificate pinning, which prevents proxy inspection. This is a security feature and cannot be easily bypassed.

💡 Best Practices

Disable proxy when done testing - Remember to turn off the proxy settings on your mobile device when you're finished
Use filters - Set up Charles filters to focus on specific domains or URLs
Save sessions - Use File → Save Session to keep recordings for later analysis
Clear sessions - Use Proxy → Clear Session to start fresh

🚀 Next Steps

Now that Charles Proxy is set up, you can:

🔍 Inspect API requests and responses
✏️ Modify requests using Breakpoints
🐌 Throttle bandwidth to simulate slow connections
🔄 Record and replay sessions for debugging

🛠️ Useful Charles Proxy Features

Breakpoints: Pause requests/responses to modify them
Map Remote: Replace remote resources with local files
Throttling: Simulate different network conditions
Repeat: Replay requests to test API behavior

💡 Pro Tip: Create a dedicated WiFi network or hotspot on your computer for testing. This makes it easier to manage proxy settings without affecting your main internet connection.

📚 Resources

Have questions or run into issues? Feel free to reach out!